MR. GROVE ON THE ELECTRO-CHEMICAL POLARITY OF GASES. 
97 
the chemical vieu", as othei’vvise we can scarcely imagine electricity as effecting in the 
instances givxn a merely physical separation; it may indeed be said that there is 
composition and decomposition produced by the same discharge, but this is very 
difiicult to conceive, and can hardly apply to the cases of oxygen with nitrogen and 
of carbonic oxide. 
In the experiments I have detailed, the flame or visible effect of the electric dis- 
charge coincided with the chemical effect ; when the plate was positive, a small 
globule of flame of a purple colour was visible on the part of the plate attacked, and 
a bluish flame extended over an inch or more of the needle. When the plate was 
negative, a wider and less defined disc of blue flame extended over the part of the 
plate opposed to the positive point, like a splash of liquid thrown upon it, and a 
pencil of light appeared on the point. Sometimes, but not always, this flame avoided 
the oxidated portion, probably from its inferior conducting power; and when this 
was the case reduction took place in a much slighter degree, or not at all ; sometimes, 
and I observed this particularly with bismuth, the flame attached itself to the 
oxidated portion, and then reduction immediately followed. Here, as in all the 
electrical phenomena that I can call to mind, we get the visible effects of electricity 
associated with physical changes in the matter acting, changes of state in the termi- 
nals, polarization of the intervening medium, or both*. These experiments furnish 
additional arguments for the view which I have long advocated, which regards elec- 
tricity as force or motion, and not as matter or a specific fluid -f-. 
The chemical polarity of gases shown, as I believe, in this paper, associates itself 
with an experiment which I made known in a lecture at the London Institution in 
the year 1843:|:, and which was subsequently verified by Mr. Gassiot§ with more 
perfect apparatus than I possessed, viz. that when discs of zinc and copper are 
closely approximated, but not brought in contact, and then suddenly separated, 
effects of electrical tension are exhibited, the one disc making the electroscope 
diverge with positive, and the other with negative electricity, showing that the 
effects ascribed by Volta to contact can be produced without contact, and by mere 
approximation, the intermediate dielectric being polarized, or a radiation analogous, 
if not identical, with that which produces the images of Moser taking place from 
plate to plate. 
The present experiments also associate themselves with the gas battery, where, 
though an electrolyte is used as the means of making the action continuous, or pro- 
ducing what is called current electricity, the initiating effect is gaseous polarity, the 
films of gas in contact with the respective plates of platinum having antithetic che- 
mical and electrical states. 
* Gases at present believed to be elementary, probably undergo a quasi chemical polarization by electricity ; 
thus portions of oxygen are changed to ozone, &c. See a recent paper by MM. Feemy and E. Becqueeel, 
Comptes Rendus, Paris, March 15. — Note added to the Proof, W. R. G. 
t Printed Lecture at the London Institution, 1842, p. 28. Correlation of Physical Forces, p. 48, 
J Literary Gazette, 1843, p. 39. § Philosophical Magazine, October, 1844, 
MDCCCLII. O 
